Search results for "Composite"
showing 10 items of 4584 documents
Measuring investor sentiment in the stock market
2011
Recently, investor sentiment measures have become one of the more widely examined areas in behavioral finance. A number of measures have been developed in the literature without having been fully validated, and therefore leaving in question which measure should be used for empirical exploration. The purpose of this study is to examine the relative performance of a number of popular measures in predicting stock returns and to test the relative efficacy of a hybrid approach. Using a panel of investor sentiment measures, we develop a new measure of sentiment which combines direct and indirect sentiment measures. Our results show that our composite sentiment index affects the returns of stocks …
Non-linear System Identification with Composite Relevance Vector Machines
2007
Nonlinear system identification based on relevance vector machines (RVMs) has been traditionally addressed by stacking the input and/or output regressors and then performing standard RVM regression. This letter introduces a full family of composite kernels in order to integrate the input and output information in the mapping function efficiently and hence generalize the standard approach. An improved trade-off between accuracy and sparsity is obtained in several benchmark problems. Also, the RVM yields confidence intervals for the predictions, and it is less sensitive to free parameter selection. Teoría de la Señal y Comunicaciones
Model of ageing inception and growth from microvoids in polyethylene-based materials under AC voltage
2008
Several degradation mechanisms may affect polymeric insulation system reliability. Some authors postulate that, even in a perfect dielectric, nanoscale cavities can enlarge due to various mechanisms (from mechanical fatigue to lowering of the degradation reaction energy barrier) up to a point where highly energetic phenomena, which bring about breakdown, can be incepted. Other authors are more focused on the inherent limits of manufacturing processes, which leave cavities within the insulation system whose size is large enough to cause electron avalanches, thus a measurable partial discharge (PD) activity, from the time the system is put in service or as a function of external factors (e.g.…
Advances in Anodic Alumina Membranes-based fuel cell: CsH2PO4 pore-filler as proton conductor at room temperature
2009
Abstract Anodic alumina membranes (AAM) filled with cesium hydrogen phosphate proton conductor have been tested as inorganic composite electrolyte for hydrogen–oxygen thin film (≤50 μm) fuel cell (TFFC) working at low temperatures (25 °C), low humidity ( T gas = 25 °C) and low Pt loading (1 mg cm −2 ). Single module TFFC delivering a peak power of around 15–27 mW cm −2 , with open circuit voltage (OCV) of about 0.9 V and short circuit current density in the range 80–160 mA cm −2 have been fabricated. At variance with pure solid acid electrolytes showing reproducibility problems due to the scarce mechanical resistance, the presence of porous alumina support allowed to replicate similar fuel…
Fracture Toughness of PIR Foams Produced from Renewable Resources
2012
Rigid low-density closed-cell polyisocyanurate (PIR) foams are used primarily as a thermal insulation material. Traditionally, they are manufactured from constituents produced by petrochemical industry. Introducing renewable materials in PIR formulation brings definite economical and environmental benefits. Fracture toughness of PIR foams obtained from renewable resources (with the polyol system comprising up to 80% of rapeseed oil esters) and petrochemical PIR foams has been characterized experimentally, by compact tension tests, for mode I crack propagation along the rise direction of the foams.
Reprocessing of PLA based nanocomposites: Effect of nanofiller
2017
Several studies investigated the effect of the reprocessing on the properties of PLA. However, recycling of PLA-based nanocomposites was not been investigated in depth so far. PLA is susceptible to thermo-degradation during melt processing operations. For this purpose, the study of thermo-mechanical degradative phenomena associated to its re-processing is of great concern in order to assess the possibility of recycling PLA-based nanocomposites. This work aims to evaluate the effect of reprocessing on morphology and properties of PLA reinforced with different nanofillers, i.e. hydrotalcites (HT) and graphene nanoplatelets (GnPs), pointing out on the role of the nanofiller.
Dependence between aging treatments and residual stresses on composite laminate
2006
International audience; The objective of this paper is to study the influence of residual stresses due to fabrication conditions on the thermomechanical behavior of carbon/epoxy laminate structures (cross ply). These studied laminates have undergone various cycles of thermal aging. The addition of a post-cure cycle after the end of the initial cycle makes it possible to reduce the residual stresses level. The incremental hole-drilling method is used to measure the residual strain in the laminates. These measured strains and the numerical calibration coefficients obtained by the finite element method allow to calculating the residual stress distribution in composite depth. The obtained resul…
From Waste to Resource – Utilising Residue from Ready-Made Concrete as New Aggregate
2021
Abstract A new admixture is available, to reduce the sludge produced from the cleansing of production and transportation equipment in the fresh concrete industry. The result is agglomerations of hardening concrete, that might be utilised for aggregate. Utilisation depends on adequate properties. This paper reports from investigations on the physical and mechanical properties of the aggregate and discussions on the performance relative to natural and recycled aggregates and towards requirements for utilisation. The findings indicate substantial potential for utilisation, supporting the reduction of waste for deposit and development of the concrete industry towards a circular economy.
Effect of 2% Chlorhexidine Following Acid Etching on Microtensile Bond Strength of Resin Restorations: A Meta-Analysis.
2019
Background and Objectives: The aim of this systematic review was to examine the effect of 2% chlorhexidine following acid etching on the microtensile bond strength of resin restorations for different follow-up times. Materials and Methods: A thorough search of PubMed, Scopus, and Embase databases were conducted. In vitro experimental studies or in vivo studies published up to December 2018 with an experimental group treated with a 2% chlorhexidine solution following acid etching and a control group were included, wherein the final restoration used a resin composite in both the groups. Results: Twenty-one articles were identified for qualitative analysis and 18 for meta-analysis. The differe…
Sensing properties of ZnO nanostructured layers
2017
Nanostructured ZnO layers have been deposited onto SiO 2 /Si substrates by spray pyrolysis, with previously patterned interdigitated gold electrodes. We have then measured the capacitive and resistive response against ambient parameters such as relative humidity and illumination.